Demographic Surveillance Systems (DSS) around the world have been a crucial tool to evaluate public health intervenfions and conduct relevant epidemiological studies in areas where basic demographic, social and health data are not available. DSS field sites confinuously collect data on births, deaths (including causes) and migration which provide an important resource for evaluating the impact of health care interventions. They also offer an interesting starting point for new studies. The goal of Scientific Core C is to establish a Demographic Surveillance System covering over 125,000 people in Muzaffarpur, one of the Visceral Leishmaniasis (VL) endemic districts in Bihar (India) in two phases. During phase-1, the DSS will be developed in the area where the ongoing TMRC project is implemented (85,000 people). In phase-2, DSS will be extended to the adjacent areas ofthe current TMRC area covering another 40,000 people where the VL prevalence is expected to be high as the coverage by the elimination program is low. The TMRC-lndia DSS will be the first demographic platform in a VL endemic area and it will be pioneering on VL research. The TMRC-lndia DSS will be: 1. A training platform for local staff and researchers in epidemiology, demography, entomology, DSS management and other disciplines related to intervenfion studies. 2. A research platform to conduct field studies for projects 1 and 2 in the current proposal as well as future epidemiological and intervenfion studies on VL (i.e. vaccine trial) and other disease or social issues relevant in rural Bihar. The Scientific Core C is designed to ensure that the TMRC-lndia DSS becomes a stable and solid research and training platform in India. This will promote the long-term collaboration between the different participants in this proposal and will attract new institutions and researchers.